The inclusion of Utroms, planned or a retcon?

[neatoman]

Right, so do you think the inclusion of the Utroms was planned or a retcon?

To me the answer is obvious, it's a retcon and a rather clunky one at that, the implementation of the Utroms is simply too sudden and inconsistent to be anything but a retcon. Up until Bishop shows up and explains the concept of what the Utroms are, we only ever see the species represented by and referred to as the Kraang. Anytime we got any clarification regarding their biology, homeworld or history it never mentioned anything about how they used to be different or how there are ones of their kind outside of their collective. The closest thing to foreshadowing is that when Raph ends up in the body of Kraang, the other Kraang are worried about his appearent lack of conformity. Of course, Sub-Prime is clearly an individual and that isn't presented as a problem, even if it seemed odd. Not even the episodes right before Bishop shows up bothers to us any hints. What's probably the most damning piece of evidence that it's just a retcon is the fact that we're given two contradictory explainations for what the Utroms are, with season 3 claiming they're Kraang who have detached themselves from the hivemind, but season 4 instead claiming the Kraang are Utroms forced into an unnatural hivemind. The Utroms and the Kraang can't both be the natural state of the species, that alone is evidence that something wasn't given the proper rewrite in time.

If this had been intended from the start, or even as late as halfway through the production of season 3, then there would have been some foreshadowing. Some Kraang failing to take orders for mysterious reasons, some Kraang unexpectedly helping the Turtles out, depiction of some Kraang forced to go through some procedure against their will, etc. There are so many better ways to introduce this concept than to have a character show up and explain the concept as it's being introduced.